Incline press IS going to work the shoulders especially if you use heavy weight, also bench press of course. Upright row Will work your rear delts. However power cleans are my all time favorite exercise and not only have they made my rear delts huge, my entire back and hamstrings. I have a questoin however?
How is this going to increase your punching power?You don't punch with just your shoulders do you?You should think about doing power/compound movements. I never work my front delts. They are huge from simply benching. And throwing punches does work your shoulders but i'm not sure thats the apex thats going to generate more punching power, i suppose it could, but when you talk about increasing punching power...its a matter of technique, style, power, and some would say possibly genetic forces at work...its an interesting topic but not so simple to pin down.